The present disclosure relates generally to a contact assembly, and particularly to a rotor assembly for a contact assembly.
Contact pairs are commonly arranged upon one movable rotary contact arm. When an overcurrent condition exists, electromagnetic forces cause the rotary contact arm to separate from fixed contacts against the closing force of one or more contact springs.
The rotary contact arm is typically connected to the contact springs via pivotal links. During quiescent operation, the contact springs provide a force to the rotary contact arm via the links in a direction as to drive the rotary contact arm into the fixed contacts. Upon short circuit condition, for example, current levels at or above the “withstand level” of the interrupter, the electromagnetic forces generated between the fixed contacts and the rotary contact arm causes the rotary contact arm to rotate away from the fixed contacts. If the overcurrent level reaches or exceeds the “let-through level”, the spring force passes a point commonly referred to as the “overcenter” position and the rotational direction of the contact spring force changes, i.e., the contact springs provide a force to the rotary contact arm via the links in a direction as to drive the rotary contact arm apart from the fixed contacts.
The rotary assemblies of prior systems use compression springs to provide the spring force. Compression springs are coiled helical springs that resist a compressive force applied axially. Such rotary assemblies are designed such that assembly time is high, and does not meet top-down assembly criteria. Furthermore, these systems require complex assembly jigs and fixtures.